We're going get to the news for you, but before I tell you anything else, I want you to listen to this warning. This breaking news involves pictures and video from Syria that show some very graphic images. It's of men, women and children that our sources tell us are suffering from a chemical weapons attack. Specifically here, it's sarin gas. And again, you're about to see some graphic video so please, be prepared for this.

Here it is. Syrian people of all ages dead or dying or convulsing. Clearly sick from something. These images were shown to senators in a classified briefing just two days ago. And Intelligence Committee chairwoman Diane Feinstein called them, and this is a quote, "horrendous," and said they gave her no doubt that somebody deployed chemical weapons against civilians in Syria. We're all over the world today. We're covering this potentially game changing breaking news. Nic Robertson is in Beirut for you. And Nic, I want to hear your reaction to this.

Also, Elise Labott is in Paris with Secretary of State John Kerry, is spending the night. But first, I want to get to CNN's Jake Tapper in Washington on exactly what we're seeing. He's the reason why we got these videos. I want to talk about what we're seeing here and how we know they are the real deal, Jake.

JAKE TAPPER, CNN CHIEF WASHINGTON CORRESPONDENT: CNN has obtained these 13 shocking videos shown to a key Senate committee Thursday which show what the intelligence community describes as victims of a sarin gas attack. And I must warn our viewers that the videos are quite disturbing.

The videos were shown Thursday in a classified briefing to members of the Senate intelligence committee. It's chair Democratic Senator Diane Feinstein of California had requested that the intelligence committee put the DVD together to show this evidence of a chemical weapons attack. She's advocating for military intervention in Syria. The images are shocking to watch. Young children convulsing on the floor, close upshots of people apparently dying. Lines of what seems to be dead bodies shrouded in neat rows. While the images are disturbing. We should note that these videos do not prove that the Assad regime carried out these attacks. That's the claim the U.S. government is making - they say based on other information that CNN has not verified.

As I said these clips were shown to the Senate intelligence committee but not yet to members of the House of Representatives. We could expect them to see those images in one of their classified briefings coming up. Back to you.

LEMON: All right. Jake, thank you very much. I want to get now to Nic Robertson. He's in Beirut. Nic, I want you tell me what your reaction to seeing those videos. Could this be the smoking gun, so to speak, that may change some minds around the world about Syria?

NIC ROBERTSON, CNN SENIOR INTERNATIONAL CORRESPONDENT: These videos are really hard to watch. I have seen some of them on YouTube before. So perhaps not a smoking gun so much as an emotional trigger here. Anyone who's watching this will find it very hard not to see the images and not to say that something absolutely must be done, that a heinous crime is being committed here. It cannot be allowed to continue.

I'll tell you something else as well, Don, that I've heard from a regional diplomatic source here as well. We saw a lot of men and boys there. He told me that a disproportionate number of women also died in this same attack because when these people are brought into hospital we can see them lying there. They are wet and they've had most of their clothes taken off. It's part of the decontamination that they go through.

Taking their clothes off, washing them with water before they put them in hospital. In these hospitals they didn't have the facilities to do that to women. They didn't have separate women's areas so many women, this diplomatic source told me, died because they couldn't be decontaminated properly at the hospitals. Any one who sees these videos and learn some of the details that we're learning about now will certainly feel a huge urge to act about what they've seen. But a smoking gun, perhaps not because it doesn't point. It doesn't connect this directly to Bashar Al-Assad. That's what the videos can't show us at the moment, Don.

LEMON: Yes, and Nic, as you've said before, some of these videos, many of them have been seen on YouTube before. They've been out there on the internet. But what they did was put them all together succinctly so that they could show to this group of senators and to others who may be voting on whether or not there should be some military action in Syria.

ROBERTSON: What they've done is really focused, if you will, on things like the eyes. Pupils. When a human is exposed to nerve gas like sarin it contracts the pupils in the eyes. What they've done here, in these videos, is focused on the, if you will, medical evidence that will give the strongest indication of what's happening here. The shrunken pupils that the medical workers there, it pains to show. This is really trying to point out the evidence of what's happening here. The vomiting, et cetera. This is all carefully put together to really show in a very clear and precise way exactly what's happening, Don. LEMON: All right. Nic Robertson. Stand by. Nic, we'll get back. I want to get to our Elise Labott now. Elise, you're with the Secretary of State John Kerry in Paris, these are very powerful pictures. Is this what President Obama needs to shore up in his case against Syria? I mean who with John Kerry has seen these videos as well?

ELISE LABOTT, CNN FOREIGN AFFAIRS REPORTER: Well, Don, we don't know exactly which videos European allies and Arab allies have seen yet. But we know from U.S. officials that they are showing more evidence to skeptical allies that the U.S. wants to, if not join the military coalition that at least show political support.

Now Secretary Kerry referenced videos in general today saying anybody that sees these children lying there, anybody with a conscience can't help but act. That's what the U.S. is hoping is that the international community will take up its responsibility to prevent these heinous crimes from ever happening again. But here in Europe, in the European capitals and we were in Lithuania early this morning when Secretary Kerry was meeting with European foreign ministers, they want a U.N. imprint. They want to see the U.N. Inspectors report. Those U.N. inspectors that were on the ground investigating this case. They want some kind of U.N. backing.

And so the U.S. has been (INAUDIBLE) to do that because they say there's certainly is enough evidence to go it and to make a case for action against Bashar Al-Assad. But what he's hoping now is he's really trying to make a very emotional case to the European people. And today, with the French foreign minister, both of tem talking in very emotional terms about some of the videos that we've been seeing online, in these social media, about how horrific it is and how the world really needs to take a look at itself and see how it wants to act in a socialized world.

LEMON: Elise Labott, thank you very much. We appreciate that. We're going to continue to talk more about these horrific pictures that are coming in and more specifically drill in on the effects of sarin gas. Gruesome and sometimes, most times deadly.

Next our chief medical correspondent, Dr. Sanjay Gupta joins me live. He's in Beirut. He's breaking down the aftermath of a chemical weapons attack and we're minutes away from finding out the host city of the 2020 Summer Olympics games. A live report from the winning city. Straight ahead. Don't go anywhere.

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LEMON: Welcome back. I have to continue to remind you that the images you'll see this hour on CNN are extremely graphic and extremely hard to watch. But could they be the evidence that really make the case for a military attack on Syria?

CNN has obtained 13 videos that the administration has told the senate intelligence committee that they depict a gruesome - the gruesome scene of a chemical weapons attack in Syria on August 21st. CNN's chief medical correspondent Dr. Sanjay Gupta. He is live now in Beirut, Lebanon for us. Dr. these videos show people convulsing, shaking, flailing on the floor, allegedly the victims of sarin gas. What are these people experiencing here? Obvious pain.

DR. SANJAY GUPTA, CNN CHIEF MEDICAL CORRESPONDENT: Yes, you know, it's obviously very gruesome to look at as you point out, Don. The way to think about this is that sarin is really what is known as a neurotoxic agent. It sort of stimulates everything in the body sort of go haywire. So for example, frothing, and again, Don, as you point out, it's difficult to look at but the frothing at the mouth, it's just the lungs essentially starting to produce too many secretions. The muscles convulsing that you see are the muscles basically contracting and convulsing without the ability to relax.

And ultimately what causes death in people is the diaphragm which is that muscle that allows someone to take in breaths basically starts to convulse as well. It could no longer do its job and that's ultimately what leads to death. You know, it is gruesome and it could happen very quickly and it doesn't take that much of this substance, if it is sarin. It is odorless, it is tasteless. It's something that you don't know you've even been affected by until you start to develop symptoms.

And the other thing, Don, just quickly to point out, you don't even have to inhale this. Just a small drop of this stuff literally on your skin can absorb across your skin and cause problems. So even people who were exposed later on by touching it, by touching clothing can also become exposed, Don.

LEMON: Yes and Dr., again I have to continue to reiterate to our viewers home that these images are very disturbing if you're watching at home, you may want to be careful especially if you have young children in the room.

Let's talk more about that. I spoke with a chemical weapons expert last week, Dr. Sanjay Gupta, and very plainly he put it, he said it's very similar to if you spray a pesticide on an insect. It's the same sort of effect that happens. You spray it and the insect starts to wither and starts to convulse. It's the same sort of thing, right?

GUPTA: It is. In fact, it was a sort of a pesticide. A lot of these pesticides actually do have neurotoxic sort of properties to them. It's just that sarin is so much more potent which is why it went out of the realm as just simply being a pesticide to being a weapon of sorts because of the way that it's so potent and cause problems with such a small dose. But you're absolutely right. It's the same sort of mechanism. Again, this neurotoxicity. When people throw that term around, Don, what they mean is that it just basically turns on the whole body. It turns on the muscles, it turns on the secretions in the lungs and that's ultimately what causes death.

LEMON: Let's talk about the aftermath, Dr., of a sarin gas. Is there a medicine that can reverse the effects of it?

GUPTA: Yes, there are medicines that can reverse the affects. There's a couple of different medicines. One that is basically sort of works - it's called atropine. I actually have it here. Basically trying to reverse some of the effects of the sarin. Now this is a whole vial of atropine. What doctors would typically do if they have this and they think that someone has been exposed to sarin is to start giving the medicine and seeing if it's taking effect. What they are specifically looking for is to see if the secretions start to diminish from the lungs and if the convulsions in the muscles start to decrease as well.

Bu this is a pretty commonly used medication. Again, atropine, it's in just about every hospital in the world, but you have to have it present, available and ready to go if you suspect that someone has been exposed to sarin. There are other medicines that can help but that's one of the most common ones, Don.

LEMON: And Dr., you know, we've been seeing that the situation is so dire there that many people have been making these sort of makeshift masks, some out of cardboard to try to protect themselves. But as you said, you don't really need to have to breathe it in, it can just be placed on your skin and you still feel the effects of it.

GUPTA: Yes, I saw some of that video as well, Don. You know, it's kind of sad to see because you know, you get the sense clearly people are desperate to try anything. But to your point, it's not going to help. There are certain masks that if you're going to wear a mask could actually be much more effective. This is a military grade mask. This not only protects what you're actually breathing in but also to protect some of the skin on your face. You'd also obviously have to protect the other skin on your body to try and not get exposed to sarin.

But this would much more the sort of mask that people would have sort of benefit from us compared to some of the masks that people are making over there. But again, this is the type of thing that if you know there's been exposure, your best bet is to just run. This is a heavy gas. It tends to stay pretty localized. Just get out of the particular location. If it's on your clothes, take off your clothes, wash your skin as quickly as possible. Those are sort of the best measures if in fact there's been an exposure.

These masks, that you're showing there, Don, I mean, again, it's kind of sad because it just shows the desperation of the situation like this.

LEMON: Dr., have you been able to speak to anyone who has been affected by this particular attack, family members, friends, someone who has just witnessed it in your travels, as you've been traveling around covering this story?

GUPTA: You know, what's interesting, Don, I've been in many of the areas on the border between Lebanon and Syria and being in some of these camps, you do talk to people who are convinced that they may have been exposed to sarin. Now it's very hard to verify this. I was with a man who was convinced that his children, for example, had been exposed to sarin and were able to get out in time and not have any longer term effects from this. But the thing about it is It's tough to verify after the fact. You can find sarin in the soil. You can find it in the surroundings but it's tougher to find it in the human body afterwards. So if someone survive a sarin attack, it's quite likely that they do just fine. So it's one of these situations where you would die from the exposure but if you have just a very small exposure, not enough to (INAUDIBLE) you could do fine and it's tough to prove. But there's just so much angst about it and nervousness, tension when we talked to people in these camps. They say, yes, I think I was exposed. I think that my family members were exposed but it's tough to prove the veracity of that, Don.

LEMON: All right. Dr. Sanjay Gupta, it's almost 11:20 p.m. in Beirut where he is. Dr., thank you. We'll be seeing a lot more of you. He's going to be back really throughout the evening hours here on CNN, reporting live from Lebanon. Make sure you join Dr. Sanjay Gupta, not only at the bottom of the hour but also throughout the evening here on CNN.

In the meantime, to find out how you can help the more than two million Syrian refugees visit our impact your world page at cnn.com/impact.

We're not going to go far away from this story. Next, making your voices heard. Taking to the streets here in the U.S. to spread the word against U.S. air strikes in Syria. How Pope Francis is responding to the possibility of a U.S. military strike. Here's a hint. These are live pictures from the Vatican.

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LEMON: Very busy news day here. What you're looking at celebration because it's been announced where the 2020 summer Olympics will be. On the left of your screen, what you're looking at is the winning city. That's Tokyo and they are celebrating.

On the right of your screen, you're looking at Japan and that is - that's the Japan delegation in Buenos Aires, where the International Olympic Committee made that announcement. So lots of excitement, lots of happiness. Istanbul was also in the running, no longer. Obviously, Madrid was eliminated about an hour ago as well. So now we're looking at pictures again, from Tokyo where there are celebration on the left of your screen and also on the right of your screen, you're looking at Buenos Aires.

Now, people are very happy. So that's where the 2020 summer Olympics will be held. More to come here on CNN as we get more information on this and as people continue to be excited about winning the Olympics. Olympics in 2020 will be in Tokyo.

I want to get back now to our breaking news story. Syria and again the pictures that you're going to see throughout the evening here on CNN very, very disturbing. Very graphic. So we just want to warn you here. We're going to have to wait to see if these videos will change public opinion but for now some Americans are making it clear that they don't want the U.S. involved in Syria.

In New York there were protests. Protesters repeated the call to stay out of the war. Demonstrations there included many Syrian-Americans who worry about civilian injuries in any strike.

(BEGIN VIDEO CLIP)

UNIDENTIFIED MALE: We say no more.

UNIDENTIFIED MALE: They say more war.

UNIDENTIFIED MALE: We say no more.

(END VIDEO CLIP)

LEMON: In Washington people opposed to a military strike marched from the White House to the Capitol claiming the U.S. has no business meddling in Syria.

The violence in Syria has drawn global condemnation. Pope Francis led a prayer vigil at the Vatican today, tens of thousands prayed for peace during the four-hour event. Smaller events were held in places of worship around the world. And on his Twitter account the Catholic leader wrote all men and women of good will are bound by the task of pursuing peace.

I want to tell you that President Barack Obama is going to sit down with six U.S. networks on Monday to talk about Syria. Our guy here at CNN will be Wolf Blitzer. We'll carry that interview for you here on CNN as soon as Wolf is finished with that interview on Monday.

In the meantime, celebrations again right now in Tokyo. That city just selected to host the 2020 Summer Olympic games. Live reports from the party, next.

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UNIDENTIFIED MALE: The International Olympic committee has the honor of announcing that the games of the 32nd Olympiad in 2020 awarded to the city of Tokyo.

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LEMON: All right. I think they're happy there? That's the announcement just moments ago. And that was the reaction by the International Olympic Committee, the president announced that Tokyo will host the 2020 summer games. It's a huge win for Tokyo. The city overcame competing bids by runner up Istanbul and third place finisher, Madrid.

Let's go live straight to the winning city for reaction. Paula Hancocks, standing by for us, in Tokyo. Lots of excitement there, Paula.

PAULA HANCOCKS, CNN INTERNATIONAL CORRESPONDENT: Well, Don, you know, you would not believe (INAUDIBLE) a Sunday morning here. No one here is getting any sleep tonight. They are absolutely delighted that the games are returning to Tokyo for the first time in 50 years. It was a favorite and it did not disappoint. Tokyo (INAUDIBLE) in uncertain times and I think clearly the Olympic Committee was looking for this time around.

And of course, it doesn't harm when your prime minister is willing to duck out of a G-20 meeting early to travel to Buenos Aires to help wave the flag. And certainly I think the prime minister's presence helped this bid enough. You can hear the crowd here. (INAUDIBLE) A few die hard fans here for being here at this time in the morning. They are absolutely delighted the fact that the games are returning here. They have a strong bid. It has to be said. They have the infrastructure. They have financial security. They have political stability. The only thing they didn't have was Fukushima. That was something that was held against them. Obviously, the fact that they do have those radiation spikes, toxic water leaks in recent weeks from (INAUDIBLE) nuclear power plant, but it wasn't enough to derail this bid. So the Games in 2020 will be coming here to Tokyo. Don.

LEMON: Very interesting. They have lots of mass transportation to be able to help the people get to and fro. Paula Hancocks, again, thank you very much. Last time Tokyo hosted the games back in 1964. The games will be in Tokyo in 2020.

Thank you so much for joining us. I'm Don Lemon here in New York. At the top of the hour make sure you come back to us here. The videos of that sarin gas attack in Syria that the White House is showing members of Congress to convince them of air strikes against Syria must happen. Our chief Washington correspondent, Jake Tapper is going to join us live.

In the meantime, we're going go leave you for a little bit. We're going to CNN Dr. Sanjay Gupta for a live report for you.